Revert "Make peer recovery send file chunks async (#44040)"

This reverts commit 30b7545.

Author: dnhatn

server/src/main/java/org/elasticsearch/indices/recovery/MultiFileTransfer.java

@@ -176,7 +176,7 @@ private RecoverySourceHandler createRecoverySourceHandler(StartRecoveryRequest r
                 final RemoteRecoveryTargetHandler recoveryTarget =
                     new RemoteRecoveryTargetHandler(request.recoveryId(), request.shardId(), transportService,
                         request.targetNode(), recoverySettings, throttleTime -> shard.recoveryStats().addThrottleTime(throttleTime));
-                handler = new RecoverySourceHandler(shard, recoveryTarget, shard.getThreadPool(), request,
+                handler = new RecoverySourceHandler(shard, recoveryTarget, request,
                     Math.toIntExact(recoverySettings.getChunkSize().getBytes()), recoverySettings.getMaxConcurrentFileChunks());
                 return handler;
             }